Transport Index (TI) calculator

This calculator estimates the Transport Index (TI) for a package containing radioactive material based on a measured external radiation dose rate at 1 metre from the package surface.

The Transport Index is a dimensionless number used in Class 7 dangerous goods transport to indicate the external radiation hazard presented by a package, overpack, or freight container, and to inform handling, segregation, and control measures during transport.

What this calculator does

In transport practice, the TI is determined from the maximum radiation level measured at 1 m from all accessible external surfaces of the package, using a suitable radiation monitoring instrument.

This calculator implements the standard regulatory relationship:

  • The measured dose rate at 1 m is converted to millisieverts per hour (mSv/hr).

  • The Transport Index is calculated as:

TI=100×dose rate at 1 m (mSv/hr)\text{TI} = 100 \times \text{dose rate at 1 m (mSv/hr)}

  • The resulting value is rounded up to the first decimal place (for example, 1.13 becomes 1.2; 1.27 becomes 1.3).

  • A calculated TI of 0.05 or less may be considered zero.

Internally, the calculator normalises all inputs to mSv/hr before applying the calculation and rounding rules.

Supported dose rate units

For convenience, the dose rate at 1 m may be entered using any of the following units, with both names and abbreviations shown for clarity:

  • nanosieverts per hour (nSv/hr)

  • microsieverts per hour (µSv/hr)

  • millisieverts per hour (mSv/hr)

  • sieverts per hour (Sv/hr)

  • microrem per hour (µrem/hr)

  • millirem per hour (mrem/hr)

  • rem per hour (rem/hr)

Output and interpretation

The calculator outputs:

  • the Transport Index (TI), rounded up to one decimal place; and

  • supporting information to aid interpretation.

If the calculated TI exceeds 10, a prominent warning is displayed advising consultation with a Dangerous Goods Safety Adviser (DGSA) and/or a Radiation Protection Adviser (RPA). TI values above 10 are not normally encountered during class 7 dangerous goods transportation. This indicates a much higher external radiation hazard than normally expected and typically require additional controls and specialist review.

Important notes and limitations

  • The TI is based solely on the dose rate at 1 m and reflects external radiation hazard only.

  • The TI does not replace limits on surface dose rate, contamination checks, or other transport requirements.

  • This calculator does not assign transport category labels (e.g. White I, Yellow II, Yellow III); it provides the numerical TI value used in transport documentation.

  • Where more than one radiation type is present (for example, gamma and neutron radiation), the overall TI may need to reflect the combined contribution from each type.

This calculator implements the standard method used for packages, overpacks, and freight containers. If your consignment falls under a specific regulatory provision or special case, you should seek competent advice.